@book{DP,
  title={Design patterns: elements of reusable object-oriented software},
  author={Gamma, E. and Helm, R. and Johnson, R. and Vlissides, J.},
  volume={206},
  year={1995},
  publisher={Addison-wesley Reading, MA}
}

@book{JEEDP,
  title={J2EE design patterns},
  author={Crawford, W. and Kaplan, J.},
  year={2003},
  publisher={O'Reilly \& Associates, Inc.}
}